There are more children needing homes than there are parents to raise them. Every year, hundreds of thousands of children are taken from their biological parents' households and placed with a foster family or institution with the intent to either reunite the family if the birth parent(s) can change their lifestyle or to place the child with a new permanent home more stable than the one they were born into.
Just under half of the children in foster families are actually waiting to be reunited with their birth parents, but about a fourth of foster children are in need of permanent adoptive families. In some states, adoptive parents can be approved to foster a child in a fost-adopt or legal risk program, which means the family can adopt the child as soon as the legal work is processed to approve the adoption.
Older children are in lower demand, so to speak, than infant adoptees. Older children are thought to be more troubled and come with baggage that many adoptive parents do not feel emotionally or financially ready to take on when they decide to adopt.
There is a match for everyone, though. Older couples are known to adopt older children because they don't want to raise an infant, which is time-consuming and exhausting, and they're also more likely to adopt sibling sets because they may have an empty house from their previous children who have grown up and moved out.
To find children needing homes, check local photolistings posted by your state's public agencies.